2008/06/11 by V. A. Khodel, J. W. Clark, M. V. Zverev · 96 citations
Materials Science · Mathematics · Physics and Astronomy · #Combinatorics #Critical point (mathematics) #Geometry #Iron-based superconductors research #Mathematics #Physics #Quantum #Quantum critical point #Quantum mechanics #Quantum phase transition #Rare-earth and actinide compounds #Surface (topology) #Theoretical physics #Topological Materials and Phenomena #Topology (electrical circuits) #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.78.075120
published in Physical Review B 78(7) (American Physical Society) · 20 pages, 11 figures
arxiv created 2008/06/11 · openalex publication_date 2008/08/25 · arxiv updated 2010/04/20 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We examine the nature of phase transitions occurring in strongly correlated Fermi systems at the quantum critical point (QCP) associated with a divergent effective mass. Conventional scenarios for the QCP involving collective degrees of freedom are shown to have serious shortcomings. Working within the original Landau quasiparticle picture, we propose an alternative topological scenario for the QCP in systems that obey standard Fermi-liquid (FL) theory in advance of the QCP. Applying the technique of Poincar'e mapping, we analyze the sequence of iterative maps generated by the Landau equation for the single-particle spectrum at zero temperature. It is demonstrated that the Fermi surface is subject to rearrangement beyond the QCP. If the sequence of maps converges, a multiconnected Fermi surface is formed. If it fails to converge, the Fermi surface swells into a volume that provides a measure of entropy associated with formation of an exceptional state of the system characterized by partial occupation of single-particle states and dispersion of their spectrum proportional to temperature. Based on this dual scenario, the thermodynamics of Fermi systems beyond the QCP exhibits striking departures from the predictions of standard FL theory. Mechanisms for the release of the entropy excess of the exceptional state are discussed.